tools/vm: add .gitignore to ignore built binaries

There is no .gitignore in tools/vm, so 'git status' always show built
binaries. To ignore this, add .gitignore.

Signed-off-by: Joonsoo Kim <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

tools/vm/.gitignore

···
+slabinfo
+page-types